Fix warnings in comerr directory

Fix warnings in comerr directory

Prototype yylex in error_table.y to remove warning
Fix the bizarre definition of LOCK_ET_LIST so that it upsets neither the
compiler, nor the reader.

Reviewed-on: http://gerrit.openafs.org/http://gerrit.openafs.org/169
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Russ Allbery <rra@stanford.edu>
Reviewed-by: Russ Allbery <rra@stanford.edu>